A standard tool in general relativity is the 3+1 or ADM point of view, namely
slicing spacetime into spacelike hypersurfaces of constant time and then describing
physics in terms of time-dependent quantities on a typical such hypersurface. Much
less well-known is the 1+3 point of view, in which one foliates...
Quantum field theory has enjoyed much success, indeed for ordinary flat spacetime applications it has been experimentally verified to a great deal of accuracy. However on general cursed spacetime backgrounds there is no canonical method for constructing a quantum field theory. In 1975, Abhay Ashtekar and Anne Magnon made progress...